Transponder devices in the form of Radio Frequency Identification (RFID) tags are well known in the prior art. RFID tags come in many forms but all comprise an integrated circuit on which in use data can be stored and a coil which enables it to be interrogated by a reader which also powers it by means of an inductive (wireless) link. One use to which such transponder devices can be put is the annotation of items, such as documents, with data over and above that printed on them. For example in EP 1 076 316 A2 Eastman Kodak Company describe the use of an RFID tag of conventional form secured to a print, being an output image on a substrate, possibly of a photograph.
To communicate with such transponder devices, it is necessary for the tag to have an appropriate antenna to provide inductive coupling with the reader. It is known to provide a RFID tag on a flexible substrate with a metallic antenna provided on the substrate and connected to the tag which may be attached to other documents. for example from U.S. Pat. No. 6,019,865. Such a process can be inappropriate for some applications, and it is known from W/O10/18749 to provide a label in which an antenna circuit is provided by printing a circuit on a substrate using a conductive toner and the RFID tag is located on the label such that conductive pins on the tag pierce or engage the printed antenna circuit. This however may be disadvantageous because of the problems of forming a reliable electrical contact between the conductive pins of the RFID tag and the antenna circuit.